Transporting commodities by common rail carrier is one of the most economical and efficient means to move commodities to destination points across North America. Some railcars transport certain commodities that are toxic and dangerous, such as petroleum crude oil type products, ethyl alcohol type products, and fuel ethanol type products. For example, inhalation of petroleum crude oil vapors may cause central nervous system problems including headaches, drowsiness, and nausea and may lead to unconsciousness or death. Additionally, petroleum crude oil may cause respiratory and eye irrigation, as well as prolonged or repeated skin contact can result in irritation and dermatitis. Further, petroleum crude oil contains Benzene, a confirmed carcinogen. Additionally, for example, high vapor concentrations of ethyl alcohol and/or fuel ethanol may cause nose, throat, and eye irritation. The ethyl alcohol and/or fuel ethanol may contain toxic denaturants, wherein exposure may lead to headache, drowsiness, nausea, dizziness, and vomiting. Inhalation of concentrations of ethyl alcohol and/or fuel ethanol above 5,000 PPM may cause transient eye and nose irritation with coughing. Skin contact with ethyl alcohol and/or fuel ethanol may result in drying and cracking due to defatting and hazardous amounts may be absorbed through severely abraded skin and be irritating to the eyes. Tank cars carrying any of these commodities or any other toxic or dangerous commodities must be treated with care and safety during all operations, to include maintenance, repair, and replacement activities.
Railroad tank cars are often equipped with valves used for top loading and unloading of tank cars. These valves are generally attached to the top fittings flange by NPT threads. The top side of the valve is supplied with another NPT connection. The valve is supplied complete with a handle. These valves must be periodically repaired and/or replaced.
When these valves must be repaired and/or replaced, generally, nitrogen gas or compressed air may be used to leak test the newly installed valves on the tank cars. The nitrogen gas or compressed air may be used to pressurize the entire tank car to ensure the newly installed valves on the tank cars are leak proof. This method of using nitrogen gas or compressed air to pressurize the entire tank car can take a significant amount of time, such as 30-60 minutes per valve or tank. Additionally, nitrogen gas can be expensive or costly, costing as much as $600-$800 per tank car per leak test.
A need therefore exists for an improved procedure and testing mechanism for the valve replacement and leak detection on a tank car.